Trinuclear iminol cyanine dyes



Patented May 31, 1949 TRINUCLEAR IMINOL CYANINE DYES Alfred W. Anish, Vestal, N. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application January 19, 1945, Serial No. 573,631

14 Claims.

This invention relates to trinuclear iminol cyanine dyes and to a process of preparing the same.

Cyanine dyes containing more than two nuclei are already known. Dyes of this category are illustrated, for example, in United States Patent 2,276,554, and in British Patent 489,335. It will be noted that in the dyes referred to in these patents the nucleus appearing in the dye, in addition to the two terminal nitrogenous heterocyclic nuclei, is heterocyclic in character and of the type known as rhodanine nucleus. In these dyes,-

however, the central heterocyclic nucleus serves to supply the terminals of two distinct resonating systems.

I have now discovered a new class of trinuclear iminol cyanine dyes in which two heterocyclic nitrogenous nuclei are linked by a monomethine radical, and in which the third heterocyclic nitrogenous nucleus, though joined to the monomethine chain, contributes a terminal common to a shared resonating system involving the other two nuclei. These new dyestuffs have certain significant properties which are not possessed by the known dyestuffs. For instance, the dyes are not only excellent sensitizers for silver-halide emulsions, but also form stable silver salts with silver ions. These properties not only make the dyes valuable as sensitizing dyes, but also as filter and anti-halation dyes for silver-halide emulsions.

Accordingly, therefore, it is an object of the present invention to provide a new class of trinuclear iminol cyanine dyes.

A further object involves a method of preparing such dyes.

A still further object is to provide trinuclear iminol cyanine dyes and heavy metal salts thereof which are added to photographic emulsions, or coated thereon as an overcoating.

Other objects and advantages of this invention will become apparent by reference to the following specification in which its preferred details and embodiments are described.

I'have found that when a methylene bis-azole is condensed with a five-membered or six-membered heterocyclic ring system, in the presence of a basic condensing agent, trinuclear iminol cyanine dyes are formed which are not only excellent sensitizers for photographic emulsions, but are also excellent filter and anti-halation dyes for photographic emulsions.

The trinuclear iminol cyanine dyes prepared according to the present invention are characterized by the following general formula:

wherein X and Y are the same or different and represent the atoms necessary to complete a heterocyclic ring system of the type usual in cyanine dyes, e. g., substituted or unsubstituted indolenines, lepidines, oxazoles, oxazolines, selenazoles, selenazolines, pyridine, quinoline, thiazoles, thiazolines; diazoles and quinazolines and the corresponding substituted or unsubstituted polycyclic compounds such as benzthiazoles, benzselenazoles, naphthothiazoles, naphthoselenazoles, diazines and the like, Z represents the atoms necessary to complete a five-membered or six-membered heterocyclic nucleus, e. g., a substituted or unsubstituted barbituric acid, thio-barbituric acid, rhodanine, oxazoledione, thiazolone, pyrazolone, imidazolone, imidazoledione and the like, n represents a positive odd integer not greater than five, and R is either hydrogen or a heavy metal, e. g., silver, lead, mercury and the like.

The process of preparing the above trinuclear iminol cyanines' comprises heating on a steam bath or under reflux conditions an alcoholic solution of a methylene 'bis-azole with a five-membered or six-membered heterocyclic intermediate derived from barbituric acid, thio-barbituric acid, rhodanine, hydantoin (imidazolone) thiahydantoin (imidazoledione) oxazoledione, thiazolone or pyrazolone having a reactive acetanilido group linked to a ring carbon atom next adjacent to a keto group of such intermediate in the presence of an alkaline condensing agent.

The symmetrical methylene bis-azoles used in the preparation of the new dyes of the present invention are described in the Journal of the Chemical Society, 121, p. 464, 1922, and. the unsymmetrical methylene bis-azoles are described in United States Patent 2,323,503.

The five-membered heterocyclic intermediates derived from rhodanine, thiazolone, hydantoin, oxazoledione and pyrazolone are described in United States Patent 2,186,608 and represented by the general formula:

wherein Z and n have the same values as indicated above under the general formula. More 3 4 particularly, the compounds represented by this diluted with 5% perchloric acid solution. The general formula are as follows: 4-(y-aoetanilidodye which separated was boiled out twice with allylidene) -l-benzothiazolyl-3-methyl- 5-pyrazo- 95% ethyl alcohol and then dried. lone, 4-('y-acetanilidoallylidene) 3 -methyl- 1 EXAMPLE II phenyl's-pyra'zolone' 5'acetanilidomethylene's- 5 2-thio-3-ethyl-4-hydroxy-5-[6,6-dibenzothiazolyl allylrhodanine, 5-acetanilidopi opadienylidene-3- butadienyl(1,3) l-dihydroxazole allylrhodanin'e, Beacetanilidometliyilerie-3-phens s ylrhodanine, '5 acetanil i'domethylehe 3 ethylrhodanine, 5-acetani1idomethylene-3-ethyl-2-thio 2,4 (3,5) -oxazoledione, -(y-acetanilidoallyli '10- EH dene)-2-diphenylamino-4 (5) -thiazol'one; 5-(57- 5 acetanilidoallylidene)-3-ethyl 2-thio-2,4 (3,5)- oxazoledione, 5- -acetanilidoallylidene) 3 -iethyl- 1 phenyl 2 thio-hydantoin; '5-(5"-'acetariilido- ---0 A -pentadienylidene)-3-ethylrhodanine. 5 1 (11:5

As condensing agents employed in the-prep aration of the new dyes of the present invention, f the following may be employed: heterocyclic niw (H5 trogenous bases such as pyridine, dinithyl p'y- "2.8 grams (1 mol) of ,methylene bis-benzthiaridine, ethyl pyridine, thylmethyl pyridine, trizole and 3.3 grams (1 mol) of 5-(7-acetanilidomethyl pyridine, 'qiiinoline and the like, using allylidene) -3-'ethyl-2-thio ;4 3;5) oiiazolediene basic catalysts, such" as 'trithyl amine, tributyl were mixed-with 20c.-of dry'pyi'idine containamine, sodium or potajssium carbonate, or acid ing 1 cc. of triethylamine. The mixturew'as condensing agents suchfias acetic acid or acetic boiled under refluxfar 1% hours, cooled and anhydride. In generaL'the amount of condensthen diluted with 5"cc. of water. The mixture ing agent used may vary 'within wide limits, e. g., was stirred vig'oi'ous lyfora-few ininutes -and then from 1 to 25 mols. Concentrations ranging from further dilutedwith 10' ee-ler'water. 0h stand 1 mol to about 15 mols aretpreferred. ing an oil separated out which was segregated When 1 mol' of a=methylene bis-azole confrom the supernatant liquid-by de'cantatiozi; The

densed with 1 mol 'of -a fiveror-siX-membered 3 oil was dissolved in a=minimumamount of-nieth heterocyclic intermediate in the presence of ,aanol and diluted with 5%-per'eh-loric acid-solution.-

condensing agent, for instance. pyridine, a reac- The dye which separated was boiled o'ut twice tion occurs which maybe written as-follows: with 95% ethyl alcohol and then-dried.

coon; z ,fl H y ,l X c-cH,-c Y C|H|N(GH).=O-OO The following examples describe in'detailthe methods for accomplishing the above objects, but EXAMPLE m it is to be understood that they .ereins'eaea 1-phenyl-2-thio 3-ethy1=4hydroxy-5=[6,6-dibenzonzolyl merely for the purposeof-illustrationsnandere butadienyl (lfinrdmydmimidamle not to be construed as limitingthesc'o'pe of. .the invention.

EXAMPLE I H gi to it l 2.5 grams (1 mol) of methylene bisr-benzoxgzole fi and 3.6 grams 1' mol) 0f 5e('y-acetanilidoallyli- N dene) 3 ethyl-l phenyl 2 -thiohydantoinwere 2.8 grams (1 mol) of methylene bis-benithiamixed with 20 f: drypyridine: inin 1,9 zole and 4.4 grams (1 mol) of 5-(veacetanilidoa lof trlethylamine e i wW sbQi dling lylidene) -v2-diphenyla mino-4 (5) -thiazolone were efiux for 11/2 hours, cooled and ihenrdilutedwibh mixed in 20 cc. of dry pyridine containing 1- cc. 5 CC- v W er. he n1i Xture,waS,-. 'ih 89 f of triethylamine. The-mixture was boil dnder Ously a e sd then ur her di uted reflux for 1 /2 hours, cooled and then diluted-with with 10 cc-of .water- O ndi .-o ep 5 cc. of water. The mixture 'was stirred yi gor- 0 rated out Which-Was ega edfrom thesuperously for a few minutes and then further diluted natant quidbycanta ion. flh fi lrwasflis with 10 cc. of water. Qn-standingan oil sepa- Solved in a minimum mo -ofmethanoland rated out which was segregated from the superdiluted with 5% per loric: a'cidr iQlut q :T natant'liquidby decantation. The tOiliWQSiidiS- dye which separated"wasmoiledyout twicewith solved in a minimum' amounthofemethanok'and ethyl alcohol. and then-dried.

EXAMPLE IV 1-pheny1-3-metl1yl-5-hydroxy-4- [d-benzoxa-fi-benzothiazolyl butadienyl (1,3)1-pyrazole N/o- IE; o\N/ 2.6 grams (1 mol) of Z-benzoxazolyl-Z'-benzthiazolyl methane and 3.4 grams (1 mol) of 4-('y-acetanilidoallylidene) -3-methyl1-phenyl-5-pyraz olone were mixed with 20 cc, of dry quinoline containing 1 cc. of trietliylamine. The mixture was boiled under reflux for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted with cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation. The oil Was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid solution. The dye which separated was boiled out twice with 95% ethyl alcohol and then dried.

EXAMPLE V 2-thio-3-ethyl-4-hydroxy-5-[w,w-dibenzothiazolyl hexatrienyl (1,3,5) J-dihydrothiazole 2.8 grams (1 mol) of methylene bis-benzthiazole and 3.6 grams (1 mol) of 5-(5-acetani1ido-A pentadienylidene) -3ethylrhodanine were mixed in cc. of dry ethyl pyridine containing 1 cc. of tributylamine. The mixture was boiled under reflux for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted with 10 cc. of water. On standing an oil separated out which was segregated from the supernatant liquid by decantation. The oil was dissolved in a minimum amount of methanol and diluted with 5% perchloric acid solution. The dye which separated was boiled out twice with 95% ethyl alcohol and then dried.

EXAMPLE VI 2-thio-3-allyl-4hydroxy-5- ,B ,B'dibenzothiaz olyl-ethenyl) dihydrothiazole o-o-o 1.4 grams of methylene bis-benzthiazole and 1.6 grams of 3-allyl-5-acetanilidomethylene rhodanine were dissolved in 15 cc. of dry pyridine containing 1 cc. of triethylamine. The mixture was refluxed for 1 hours, cooled and then diluted with 5 cc. of water. The mixture was stirred vigorously and then further diluted with 10 cc. of water. The oil which separated soon thickened and the liquid portion was decanted. The oil was dissolved in a minimum amount of methanol and diluted'liberally with a 5% perchloric acid solution. The dye which separated was boiled out twice with ethyl alcohol.

An ethyl alcohol solution of 20 mg. of the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromid and having a total content of 4-5% silver-halide. The dye imparts a sensitivity to about 650 m with a maximum sensitivity at about 600 my.

EXAMPLE VII 2-thio-3-allyl-4-hydroxy-5- (B,B-dibenzoxazolyl-ethenyl) dihydrothiazole Five grams of methylene bis-benzoxazole and 6.4 gramsof 3-allyl-5-acetani1idomethylene rhodanine were dissolved in 30 cc. of dry pyridine and. 5 grams of anhydrous sodium acetate added. The mixture was refluxed for 3 hours, cooled and water added to precipitate the dye as an oil. The cooled mixture was allowed to stand overnight and the solidified oil filtered ofi and washed with Water. The crude dye was re-dissolved in 60 cc. of pyridine and carefully diluted with water until cloudy. The dilute pyridine solution was chilled for 4-5 hours, and the unreacted materials filtered ofi. The filtrate was treated with a 5% perchloric acid solution until cloudy, and on standing the dye crystals separated. The dye was washed with water and dried.

An ethy1 alcohol solution of 20 mg. of the dye was incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and having a total content of 4-5% silverhalide. The dye imparts a sensitivity to about 630 m with a maximum sensitivity at about 570 mu.

EXAMPLE VIII 2-thio-3-al1yl-4-hydroxy-5- (B-benzoxazolyl-B-benzothiazolylethenyl)-dihydrothiazole An ethyl .alcohol solutionof 20 mg. of rthedye was :incorporated in 1 kilogram of silver chloride emulsion containing a small amount of silver bromide and havinga total content ore-5% silvet-halide. The dyeimparts-a sensitivityito about 640 m with a maximum sensitivity at :about'590 m l.

EXAMPLE 3.4 grams of 3-all yl-5-acetanilldopropadienyl- 1,3-rhdanine, and 3.2 grams of methylene bisbenzthiazole were dissolved in 39.00. of dry pyridine and 0.5 cc. triethylamine added. The mixture was heated on a steam bath for 30 minutes.

The reaction mixture was diluted out with an equal volume of water. On standing an oil separated which was separated from the supernatant liquid by decantation. The oil was dissolved in a-minimum amount of --methanol and diluted with a 'perchloric acidsolution. The dye which separated was boiled out twice with 95% ethyl alcohol.

An ethyl alcohol solution of '20 -mg. of the dye was incorporated in 1 kilogram 'of silver chloride emulsion containing a small amount of ;-silver bromide and having a total content-of 4 5% silver-halide. The dye imparts-a sensitivityto about 620 him with a maximum sensitivity at about 570mg.

EX MBL X 6 -hydroxy-2,4-diketo-5- [dddibenzothiazolykbn tadienyl (1,3)]-tetrahydropyrimidine On standing, an oil separated out 2;? grams (1 mol) of 2.benZQX8izolyl-,2-bengothiazolyl methane and 2.9 grams (1,111 01 of 5- (y-acetanilidoallylidene) -2-thio.-4,6-.dikctohexahydropyrimidine were mixed with cc, of-dry pyridine containing 1.0 cc. of triethylamine. The mixture was boiled under reflux for 1. hours, cooled and then diluted with 5 ,cc. of water. The mixture was stirred vigorously for a few minutes and then further diluted withlll cc. of water. On standingan oil separated out which was segregated from the supernatant liquid by decantation. The oil was dissolved ,in;a minimum amount of methanol and.di1,uted with 5% .perchloric acid solution. The dye which separated was boiled out twice with 95% ethylalco, hol and then dried.

In the preparation of emulsions containing these trinuolear iminol cyanine dyes, :the dye may be dissolved in methyl or ethyl alcohol and a volume of this solution containing from 5 to 59 milligrams of the dye added to a liter of emulsion. While in general practice git may not be necessary to add the dye in amounts-larger than those above given, generally for satisfactory results, amounts usually ranging from 5 to milligrams are sufiicient to obtain the maximum sensitizing effect. However, I do not wish to limit my invention to the quantities just indicated, the most suitable amqunt will in each case be found by a few comparative experiments. The dyes may be added to the emulsion in the form of solutions. Suitable solvents as indicated in the examples are the alcohols, for instance, methyl'or ethylalcohol whichmay be anhydrous or diluted with a small volume of water. In actual practice, the dyesrare appliedto theemulsion during any stageof its production, however, they are preferably added to the finished.emul. sion before being cast.

The aboveexamp es are illustrative only, and should not be construed as limiting the .invene tion, since ,it willbe apparent to thpseskilled in the. art, that the dyes of the present invention ma e nco po ed i to ph t gra hic emulsions .by methods ,other than those described herein.

The dyes of this invention are iurthercharacterized by their ability to form insoluble heavy metal salts, e. g., silver, lead and mercury salts, due to the presence of a salt-forming hydroxyl group in the merocyanine nucleus. :for example, in the presence of silver ions insoluble silver salts are.formed. These silver salts, moreover, are soluble in photographic processing baths, such as sodium thiosulfate. Accordingly, the dyes of this invention are readily applicable as non-diifusing photographic filter and antihalation dyes in photographic materials in the form of their silver salts. The dyes may be incorporated directly into the photographic emulsion or applied in aknown manner as an inter- 9 mediate layer between the support and emulsion, as a backing layer on the rear surface of the emulsion support, or as an interlayer between the two emulsion layers.

The following examples illustrate the use of the dyes of this invention in the form of silver salts as filter and anti-halation agents.

EXAMPLE XII A photographic filter layer was prepared by mixing the following ingredients to form a colored silver salt dispersion in gelatin:

Solution A 2-thio-3-allyl-4-hydroxy-5- (pp-dibenzoxazolyl-ethenyl) dihydrothiazole grams 2.7

Water cubic centimeters 100 Sodium carbonate (anhydrous) grams 2.1

Gelatin (10% solution) cubic centimeters 25 Solution B Water cubic centimeters 100 Silver nitrate grams 1.7

Solution Gelatin (10% solution) cubic centimeters 100 Solution B was added to Solution A with rapid stirring. After several minutes, Solution C was added. The silver of the silver nitrate formed a silver salt with the hydroxy group of the dye in the gelatin solution. The final gelatin suspension thus obtained was then coated on a photographic film in the customary manner to serve as a yellow filter layer for blue light absorption. The silver salt of the dye is nondifiusing.

The amount of silver salt used according to the present invention will vary somewhat, depending upon the color desired. In general, an amount more or less than that given in Example XII may be used for satisfactory results.

For the production of anti-halation coatings, the trinuclear iminol cyanine dyes of the present invention are incorporated into gelatin, treated with silver nitrate, and the silver salts dispersions thus obtained are cast in a known manner as coatings as an intermediate layer between the support and the emulsion or as a backing layer on the rear surface of the emulsion support, or as a support on the emulsion, when the material is intended to be exposed through the support.

EXAMPLE XIII A photographic anti-halation layer was prepared by mixing the following ingredients to form a colored silver salt dispersion in gelatin:

Solution A 1 -phenyl-3-methyl -hydroxy-4- (B-benzoxazolyl-5-benzothiazolylbutadienyl (1,3)1-pyrazole grams 7.0 Water cubic centimeters 200 Sodium hydroxide (4%) do 7.5 Gelatin solution) do 100 Solution B Water cubic centimeters 100 Silver nitrate grams 3.4

Solution C Gelatin (10% solution) -cubic centimeters 300 Solution B was added to Solution A with rapid stirring. After several minutes, Solution 0 was added. The final gelatin suspension of the silver salt thus obtained was coated on a support in the customary manner as an anti-hajlation layer.

The filter and anti-halo coatings prepared as described above have been found to have particularly good filter and anti-halant properties and to have no effect on the normal keeping properties of the light-sensitive layer.

While the present invention has been described in considerable detail with reference to certain preferred procedures, materials and uses, it is understood that the new class of trinuclear iminol cyanine dyes and their use as sensitizing, filter and anti-halation dyes is not limited thereto, and that numerous variations and modifications described in the foregoing specification may be made as, for example, the dyes which contain a merocyanine nucleus, e. g., oxazoledione, hydantoin (imidazolone) and rhodanine nucleus, as illustrated in Examples 2, 3, and 5 to 9 inclusive, may be further treated with a quaternizing compound such as methyl iodide. The quaternated compound is then condensed under reflux conditions with a cyclammonium base or salt such as N-methyl-2-methylbenzthiazole (having a reactive methyl group in the alpha position to the nitrogen atom) in the presence of a condensing agent such pyridine, quinoline and the like. In the first reaction (alkylation), the trinuclear iminol cyanine is modified to the extent that the nitrogen atom in the 3-position of the oxazoledione, hydantoin or rhodanine ring is quaternized and the sulfur atom in the 2-position is converted to a thioether group. In the second reaction (condensation), the alkylated trinuclear iminol cyanine condenses with a cyclammonium base or salt whereby new compounds, which are also useful as sensitizers, filter and anti-halation agents, having the following general formulae are obtained:

wherein R, X and Y and n have the same values as in the above general formula, R1 represents an alkyl, alkylene or aryl radical, R2 represents an alkyl, X represents an acid radical of the type usual in cyanine dyes and Q represents either nitrogen, oxygen or sulfur. All such modifications and variations are within the scope of this invention as defined by the appended claims.

I claim:

1. Trinuclear iminol cyanine dyes characterized by the following general formula:

amigos-e wherein- X and Y represent the atoms necessary to completes? het'ei'ocyclic nitrogenous ring systerh of the type usual in cyanine dyes and selected' from the class consisting of indolenines, lepidlnes'; oxazoles; ox'azolines', s'elenazoles, selenazolines; pyridines; quinolines, thiazoles, thiazolines, diazoles; and quinazolines', Z represents the" atoms necessary to complete a member selectedfrom the class consistin of a five-membeted and siX-membered heterocyclic ring system, wrepresent's a positive odd integer of from one to five; and His a member selected from the ol'assconsisting of hydrogen and aheavy' metal;

2.- The'coriipoun'cls as defined in claim 1 whereiri Rnofi the OR group is replaced by silver.

A trinuclear im-inol: cyanine dye and the hydroxy heavymetal salt thereof corresponding to the formula:

41 compound as defined in claim 3 wherein the hydr'o'xy heavy menu salt is silver.

5': A t'rmuciear iminol cyanine dye and the hyrori'y" heavy metal salt thereof corresponding to'the formula:

Ho-t t=s 6. The compound as defined in claim 5 wherein the hydroxy heavy metal salt is silver.

7. A trinuclear iminol cyanine dye and the hydroxy heavy metal salt thereof corresponding to 8*.- The compond'as defined in claim! wherein the hydroity heavy metal salt issilver.

9. The processof producing trinuclear i'minol cyanines which comprises heating a methylene bis-'azole with a; compound of the following for- 'mulaz coon: 2 clHn i-- oi1 -o --c=o wherein Z-representsthe atoms necessary to complete a member selectedfrom the class consisting of a five-membered and six-mombered heterocyclic ring system; andn represents a positive odd integer of from one to five.

10.-'L-1 'ie process according to claim 9 wherein the heating-- is conducted iii the resence or a neterocycn'c nitrogenous base containing atertiary mine.

11-.- 'I-nepruces's Of producin'g'a trinuclear'i'ril'ihol cyanine dye which comprises heating one molecular proportion of methylene bis-benzoxazole with one" mol'eci'il'ar proportion of 3'-allyl--5'-acetanili'domet'hylene'rhodanine.

12. The process according to claim 11 wherein the heating is conducted in the presence of pyridin cfdfitairii'rig' trie'thylamine.

1 3. The process ofpi 'o'ducing a tri'nuclear i'mifi'ol cyanine dye which comprises heating one molecular proportion of methylene bis-benzthia'z'ole with one molecular'propo'rt'ion' of 3'-'allyl-5- adtelriiliiioprdpadienyl-1.3=rhbdanine.

14. The process" ofproducing a trinuclear iminol cyanine dye which comprises heating one friol'e'ciilar proportion of 2Z2-benzoXazolyl-benztliii'aizolyl n ietliafie with one m'olecul'ar proportion of 3-allyl-5-acetanilidomethylene rhodanine.

ALFRED W. ANISH.

REFERENCES CIT-ED The" following" references are of record in the file of this pateritr' STATES PATENTS Name Date 23 112115 Bi o Mar 1942 2,323,504 Wilson July 6, 1943 ingest? Kendall Oct. 2, 945 2388;963 Kendall Nov. 1, 1945 FQREIGN PATENTS Nuirih'er Qoii-ntry Date 549,202 Great Britain "1942 549,204 Great'Britain 1944 Certificate of Correction Patent No. 2,471,996. May 31, 1949.

ALFRED W. AN ISH It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 8, Example XI, lines 12 to 14, for that portion of the formula reading THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents. 

